The short and the long of those emails by (lead Tor developer) Roger
Dingledine is:

"Yeah. This happened in mid 2006. I don't know why some random person
just picked it up now.

We (mainly Steven Murdoch and Richard Clayton) tracked down the fellow
running them. It turned out to be an innocent mistake. He's still
running quite a few, on the same network, but now he sets the MyFamily
torrc option on them.

This issue also prompted us to speed up the fix/feature in 0.1.2.1-alpha:
"Automatically avoid picking more than one node from the same
/16 network when constructing a circuit.""

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PREVIOUSLY: BB reader David says,

Since TOR is an occasional pet topic at boingboing I thought this might be interesting. An example of the NSA spying program we know about, or something else? Either way, some sneaky peekers are trying to peel the onion. Link to txt file, excerpt here:

"High-traffic Colluding Tor Routers in Washington, D.C. Confirmed:
A group of 9 Tor routers also functioning overtly or indirectly as Tor exit nodes have been observed colluding on the public Tor network."